The present invention relates to syringe systems and injector systems and, more particularly, to medical syringe systems and injector systems with collapsible cartridges for containing and pressurizing the injection fluid.
Syringes have been used in the medical arts for many decades now. In general, all syringes include a barrel or chamber into which a fluid to be injected is charged. The syringes also include a reciprocating plunger that is advanced to pressurize the fluid within the barrel for injection and retracted to draw fluid into the barrel.
In recent years, a number of injector-actuated syringes and powered injectors for use in medical procedures such as angiography, computed tomography, ultrasound and MRI have been developed. For example, U.S. Pat. No. 4,006,736 discloses an apparatus for injecting fluid into the vascular system of a human being or an animal. Likewise, U.S. Pat. No. 4,677,980 discloses an angiographic injector and syringe wherein the drive member of the injector can be connected to, or disconnected from, the syringe plunger at any point along the travel path of the plunger via a releasable mechanism. Further, U.S. Pat. No. 5,383,858 discloses a non-pressure-jacketed front-loading syringe and injector system.
Although numerous advances have been made in syringe technology, numerous problems persist. For example, plungers used in current syringes typically comprise an elastomeric plunger cover that forms a sliding seal with the inside of the syringe barrel, usually requiring a lubricant to reduce frictional forces. Although maintenance of sterility is of the utmost importance in many medical procedures, lubricants used in connection with the plunger may come into contact with and contaminate the injection medium. Moreover, the inside wall of the syringe barrel may become contaminated during the reciprocating motion of the plunger.
In addition to maintaining sterility, it is also very important to inject a predetermined amount of material in many medical procedures. Often, if the wrong amount of injection medium is drawn into the syringe and injected, the procedure must be redone. In certain cases, disposable syringes are supplied in a xe2x80x9cprefilledxe2x80x9d state to assist in ensuring sterility and a controlled injection volume. However, current prefilled syringes are rather difficult to produce and require specialized materials.
It is very desirable to develop syringes that reduce or eliminate the problems discussed above and other problems associated with current syringes.
In one embodiment, the present invention provides a syringe system including an elongated shell, a pressure member slidably disposed within the elongated shell, and a collapsible cartridge. The collapsible cartridge is inserted within the elongated shell. The collapsible cartridge collapses as the pressure member is advanced within the elongated body to pressurize fluid within the collapsible cartridge. The collapsible cartridge preferably further includes a passage through which the fluid passes when pressurized by the pressure member.
The collapsible cartridge is preferably fabricated from a pliant or collapsible film suitable to withstand pressures commonly experienced in medical procedures such as angiography, computed tomography, ultrasound and MRI when the collapsible cartridge is pressurized within the shell. The shell preferably acts as a pressure jacket to assist in withstanding such pressures.
The pressure member of the syringe system may include an attachment mechanism to form an attachment with a drive member of a powered injector, as known in the art. For example, the attachment mechanism may be formed in the manner shown and described in U.S. Pat. Nos. 4,677,980 and 5,383,858. Alternately, however, in the event that the cartridge is prefilled with fluid, the pressure member may be designed to be xe2x80x9cpush-only,xe2x80x9d thereby not requiring an attachment mechanism to allow retraction of the pressure member for, for example, filling the cartridge with fluid.
The present invention also provides a method of injecting a fluid into a patient including the steps of: loading a collapsible cartridge for containing the fluid into an elongated shell, the collapsible cartridge comprising a passage through which the fluid passes when pressurized by a pressure member slidably disposed within the shell; and advancing the pressure member to collapse the collapsible cartridge and thereby pressurize the fluid within the collapsible cartridge.
The collapsible cartridges of the present invention may be prefilled with injection fluid before loading thereof into the shell of the syringe system or may be filled with injection fluid thereafter.
The syringe systems of the present invention are very simple and inexpensive to manufacture. For example, they greatly simplify and reduce the cost of manufacturing a disposable, prefilled syringe system that may be used with a single patient in a single injection procedure. The syringe systems of the present invention may be manually operated or injector-actuated, depending on the application. Moreover, the syringe systems of the present invention eliminate the need for a plunger that forms a seal with the inner wall of the syringe barrel. Contamination concerns arising from the use of elastomeric plunger covers and associated lubricants are thereby eliminated.